A laminate element, typically a strip or tape, for a hook and loop fastener, particularly for a diaper, has a substrate layer and a textile cover layer laminated onto the substrate layer. The cover layer has free loops for engagement of hook elements of the other fastener half, that is the hook tape or strip. This cover layer typically consists of a nonwoven material and polymer threads knitted into it and forming the loops.
The laminate forms the female part of a hook and loop fastener. When used on diapers, the laminate is applied to the front waistband region of the diaper. A hook tape, which is attached at the side of the diaper and has hooks at its free end, completes the hook-and-loop fastener. Hook-and-loop fasteners can be opened and closed many times without any deterioration of functionality. In contrast to adhesive fasteners, hook-and-loop fasteners are not sensitive to contact with skin creams or powder.
Various demands are made on a laminate for a hook-and-loop fastener on a disposable product, for example baby diapers. The material is supposed to have as low a weight per area unit as possible so that it can be produced inexpensively. In spite of its low weight per area unit, the material must guarantee sufficient hook engagement with hooks of the related hook tape. A sufficient number of freely movable loops is required, whose function is not allowed to be impaired by adhesion of the substrate layer to the textile cover layer. Last but not least, the material is supposed to have an appearance that appeals to the consumer.
A laminate having the characteristics described above is known from U.S. Pat. No. 6,647,600, where a multi-layer nonwoven laminate is provided as the textile cover layer, and where textured polymer threads are knitted into the entire nonwoven laminate to form the loops. In order to achieve a good printing surface and adhesive surface, the cover layer can optionally be laminated onto a film as a substrate layer, onto which film the print or the adhesive layer is then applied. If, according to an alternative embodiment, no substrate layer is provided, there is the disadvantage that the nonwoven laminate must have a comparatively great thickness in order to guarantee sufficient strength. If the nonwoven laminate material with the polymer threads knitted into it is supposed to be used as a substrate layer without a film, the nonwoven laminate can be provided with an adhesive on an outside layer, in order to allow attachment of the laminate, for example on a diaper. In this connection, the opposite side can be provided with an print. It is disadvantageous that the print, which then lies on the outside after attachment by the adhesive, can easily be rubbed off. In particular, undesirable contamination can occur when the laminate is used. Furthermore, because of the loops that project out of the nonwoven laminate on the one hand and the low weight per area unit that is usually aimed at for cost reasons on the other hand, a uniform print is not possible, or only possible with difficulty.
DE 10 2006 028 377 describes a textile laminate material having a substrate layer and a cover layer that are stitched together. The sewing forms loops for the engagement of hook elements on the top of the laminate material and stitches on the underside of the laminate material. The substrate layer and the cover layer can consist of nonwoven materials. Compromises have to be made with regard to the hook-and-loop properties and laminate strength, since in a warp-knitting process with the same sewing threads not only are free loops formed but also the layers are connected with one another.